Person
OutboxItem

Collab

CollabFulfillsInvite
    collab CollabId

    UniqueCollabFulfillsInvite collab

CollabRecipLocal
    collab CollabId
    person PersonId

    UniqueCollabRecipLocal collab

CollabRecipLocalAccept
    collab CollabRecipLocalId
    invite CollabFulfillsInviteId
    accept OutboxItemId

    UniqueCollabRecipLocalAcceptCollab collab
    UniqueCollabRecipLocalAcceptAccept accept